Application of so-called "dry" quick-setting mixtures (DSM) based on mineral binders as plugging material for isolation of zones of geological complications (cleaning agent absorption, water influxes and intervals of unstable rocks associated with them) required creation of a number of special devices for delivery and processing of DSM directly in the well interval to be plugged.

The branch laboratory of TTRB together with production geological associations has carried out a large amount of work on the introduction of foams as a cleaning agent ...

For engineering geology it is very important to take samples of soil with undisturbed structure. Especially difficult in this respect is the sampling of monoliths from frozen soils in the process of borehole sinking. In order to work out the technology of drilling wells in frozen soils, experiments were set up, in the course of which the main difficulty was the choice of the method of control over the state of structure preservation in the process of drilling ...

In the process of drilling, heat is generated in the bottom-hole zone due to mechanical work of the rock-destroying tool. As a result, the natural temperature and aggregate state of frozen rock cores is disturbed. Studying the mechanism of frozen rock core thawing during drilling, finding out the regularities of the thawing process for conscious regulation and normalization of its temperature regime is of practical importance.

The most important task of exploratory core drilling is to ensure high yield and quality of core - source material for geological and engineering-geological sampling. Analysis of production data of a number of organizations engaged in drilling in permafrost rocks shows that when drilling with flushing the core yield is 60-70% for bedrock with moisture content of 2 - 5% and 20-30% in rocks with moisture content of 15% and more. In production conditions very often in order to increase the core yield one switches to “dry” drilling. However, the core quality deteriorates sharply. Partial or complete thawing of the core takes place with violation of its structural characteristicsю

Successful testing of technical means and technology of drilling wells with bottom-hole cleaning by cooled compressed air, developed by the department of TTBS of LGI under the contract with the Dalstroyproekt Institute (Magadan), allowed drilling by this method in production conditions and give a preliminary assessment of its economic efficiency in comparison with the method of drilling wells in frozen rocks “dry”, i.e. without bottom-hole cleaning by any circulating agent.